<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="allCheckedHandle" />
    </label>
    <span> <span>已完成{{getFinish}}</span> / 全部{{ todoList.length }} </span>
    <button class="btn btn-danger" @click='deleteAllFinish'>清除已完成任务</button>
  </div>
</template>

<script>
export default {
  name: "Footer",
  props: ["todoList", "getAllChecked",'deleteAllFinish'],
  // computed -- 计算属性，目的是为了得到一个值
  computed: {
    allCheckedHandle: {
      get() {
        // every -- 一假即假，全真才真
        return (
          this.todoList.every((item) => {
            // 遍历todoList，如果每一项都是选中状态，则item.done为true，every的返回值为true，选框状态就为true
            // 如果有一个没选中，则item.done为false，every的返回值为false，选框状态就为false
            return item.done;
          }) && this.todoList.length !== 0
        );
      },
      set(done) {
        this.getAllChecked(done);
      },
    },

    getFinish() {
      return this.todoList.reduce((p, c) => {
        return c.done ? p + 1 : p;
      }, 0);
    },
  },
};
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>